Figure 5. Differentiation of Mesp1-CPCs from cardiac mesoderm into cardiac myocytes requires inhibition of canonical Wnt signaling.

(A) Canonical Wnt inhibitor IWR1 limited the appearance/expansion of Mesp1-CPCs induced by BMP4. FACS analysis was performed for day 5 EBs receiving the growth factor/ inhibitor treatment as indicated. (B) Canonical Wnt inhibitor IWR1 (I) induced the cardiac program at the cost of other cardiovascular lineages. Mesp1, in the presence of BMP4 (B), Pecam1, Acta2 (alpha-smooth muscle actin), and αMHC were assayed by real-time RT-PCR. *p < 0.05 versus control cells; N ≥ 3. (C) Canonical Wnt inhibitor IWR1 induced the cardiac myocyte formation. Cells were stained by antibodies indicated. The percentages were calculated as positive staining vs. nuclei. (D) Canonical Wnt inhibitor IWR1 induces the formation of cardiac myocytes from α-SMA positive cells.